Heated wiper assembly

ABSTRACT

A wiper system for vehicles is provided. The system includes a heated wiper blade assembly, a heated cowl assembly and a controller. The controller receives input from one or more sensors or systems and causes a power source to provide, reduce or stop power to heating elements in the blade and/or cowl depending upon sensed conditions. At least some components in the assembly comprise thermally conductive polymers. The system provides surprisingly advantageous results in that it is effective for melting and clearing ice and snow with a lower than expected pull on a power source such as a battery.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to provisional Application No.62/394,509 filed on Sep. 14, 2016, which is incorporated herein byreference in its entirety.

FIELD OF THE DISCLOSURE

This disclosure relates to wiper blades and related systems and methods.

BACKGROUND OF THE DISCLOSURE

Drivers use wiper blade systems to manage many types of inclementconditions, including heavy rain, sleet, snow and other wintry weather.Wiper blade systems such as those described in U.S. Pat. No. 8,431,870,herein incorporated by reference in its entirety, disclose systems andmethods for automatically turning on or turning off heating elementsembedded in a wiper blade and a method for controlling the wiper blade.

Drivers seek systems and methods that can minimize the need for manuallabor such as scraping ice from windshields. Manufacturers seek systemsand methods compatible with autonomous or connected vehicles and relatedinfrastructure and communication protocols. Manufacturers and driversseek wiper blade systems and methods that maximize effectiveness andminimize the quantity of energy needed to operate. Manufacturers anddrivers seek ease of use and repair, and the availability of readilyreplaceable aftermarket systems.

SUMMARY OF THE DISCLOSURE

Systems disclosed and claimed herein perform at least as well aspreviously known systems while requiring less power. In someembodiments, the requirement for power can be reduced by at least 10%.In some embodiments, initiation and/or adjustment of power occursautomatically depending upon sensed input. In some embodiments, one ormore components are manufactured using one or more plastic materialsexhibiting high thermal conductivity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary wiper blade system.

FIG. 2A shows components of an exemplary wiper blade system.

FIG. 2B shows components of an alternative wiper blade system.

FIG. 3 is an exploded view of a heated wiper blade apparatus.

FIG. 4 is a cross-sectional view of a heated wiper blade assembly.

FIG. 5 is a cross-sectional view of a heated cowl.

FIG. 6 is a perspective view of a cowl heat sink.

FIG. 7 is a top view of the cowl heat sink shown in FIG. 6.

FIG. 8 is a cross-sectional view of the ribbon heating element as viewedalong lines VIII-VIII of FIG. 2A.

DETAILED DESCRIPTION OF THE EMBODIMENTS

All figures and examples herein are intended to be non-limiting; theyare mere exemplary iterations and/or embodiments of the claims appendedto the end of this description. Modifications to structure, materials,the order of steps in procedures, temperature ranges, are contemplated.

Referring to FIG. 1, an exemplary wiper blade system is shown inconnection with a vehicle. The wiper blade system may be used with anyof a number of vehicles, including without limitation, the followingvehicles: heavy duty, medium duty and light duty trucks (classes 1-8),buses, and automobiles. The vehicles optionally may be made for orretrofitted for, in all in or in part, inclusion in and/or participationwith vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I)systems. In one embodiment, the vehicle is an autonomous, self-drivingcar.

The wiper blade system 10 includes wiper blades 12, 14, a cowl 16, and acontroller 18 housed in a module 20. Embodiments are contemplated wherethe processors reside outside the module and communicate with sensorsremotely or through hard wiring. As best seen in the cross-sectionalview of FIG. 4, a heated wiper blade assembly 21 includes an electricalheating element 22, a frame 24 (typically made of metal and configuredto hold elastomeric wiper blade or squeegee 26 for mounting within ahousing 28), and a squeegee 26 engaged with frame 24 and extending froma housing 28. Shapes and configurations other than that illustrated arecontemplated. Other layers could be added outside or inside the housing.The example of FIG. 3 merely assists in illustrating the conceptsdisclosed herein. The non-limiting example includes a wiper arm 30 forholding and rotationally moving the wiper blade assembly across awindshield, an adapter 32 for connecting the wiper blade assembly to thewiper arm, an adapter housing 34, a bracket 36 with electricalconnections 38 to electrical heating element 22, housing 28 and squeegee26.

In the non-limiting example, heating element 22 is in contact withhousing 34 which is in electrical communication with a power source andcontroller. Heating element 22 may comprise any of a number ofconductive materials. By way of non-limiting examples, the heatingelement may include one or more of copper, aluminum, nichrome alloysincluding 80/20, iron-chromium-aluminum alloys, copper nickel alloys,ceramics and polymers modified for thermal conductivity. As shown, thewiper blade assembly 21 includes a pair of substantially flat elongatedheating elements 22. It is contemplated that heating elements 22 couldtake on any of a number of shapes, such as to maximize surface areacontact with the housing. Without limitation, such shapes may includeelongated cylinders, elongated cylinders with an irregular surface orwith a surface of bumps (regularly or irregularly placed) that cooperatewith complementary shapes in housing 28.

Housing 28, as well as other wiper system components, may includeconductive material. In non-limiting embodiments, the housing 28, wiperarm 30, adapter 32, adapter housing 34 and/or bracket 28 can comprisethermally conductive plastics. Polymers and copolymers, especially thosethat are highly amorphous, typically have a low thermalconductivity—from about 0.11 to about 0.44 W/mK at 25 degrees C.However, additives may be employed to increase thermal conductivity. Byway of non-limiting example, such plastics may include polymers,copolymers, polymer blends and or polymer composites includingpolyamide-6 (PA6), polyamide 6-6 (PA66),poly(acrylonitrile-butadiene-styrene) copolymer (ABS), and othersmodified to be thermally conductive, such as by inclusion of thermallyconductive fillers. Such thermally conductive fillers may includenanoparticles of carbon-based fillers such as graphite, carbon black,carbon nanotubes, pitch-based carbon fiber, copper, aluminum, boronnitride, aluminum nitride, beryllium oxide, others, and combinations ofone or more. Thermal conductivity increases noticeably for relativelylow conductive filler loading and increases with higher conductivefiller loading. However, higher filler loading tends to have adeleterious effect on mechanical properties, such as reduced toughness.Suitable conductive filler loadings can range from about 20% to about80% by volume in the composite, and more preferably from about 20 or 30%to about 60 or 70%. However, higher or lower loadings are workable. Incertain embodiments, the housing 28, wiper arm 30, adapter 32, adapterhousing 34 and/or bracket 28 can comprise one or more plastics modifiedto be thermally conductive including but not limited to polypropylene(PP), liquid crystal polymer (LCP), polyphthalamide (PPA), polyamide(PA), polycarbonate (PC), Polyphenylene sulfide (PPS), and thermoplasticelastomer (TPE), which are commercially available from CoolPlastics ofUSA in Irvine, Tex. In one exemplary embodiment, the thermalconductivity of the housing may range from a value greater than 100,200, 300, 400 or 500 W/mK (with, for example, a graphite or aluminumnitride filler) to about 6,000 at 25° C. (with, for example a carbonnanotube filler).

Heating element 22 may sit on a frame in housing 28 and is in electricalcommunication with a power source and a controller. Squeegee 26 maycomprise one or more of rubber or plastic. Embodiments are contemplatedwhere the squeegee also comprises thermally conductive material. In suchembodiments, the thermally conductive material may be the same ordifferent from the thermally conductive material of the housing.

Referring to FIGS. 1, 2 and 5, cowl 16 is near a windshield 40 andincludes heating element 42 (e.g., a cable) and a heat reflector 44 towork synergistically with heated wiper blade assembly 21. Heat reflector44 can be a metal cowl liner, such as an extruded aluminum part thatconforms with, and is nested in cowl 16. Heating element 42 can be madeof the same or different material as heating element 22 and/or housing28. In one example, an electrical heating element 42 is copper combinedwith thermoplastics. Such heating element is commercially available inthe form of a cable from Backer of USA in Chicago, Ill. Heating element42 can be fixed in cowl 16 using fasteners, including adhesives ormechanical fasteners. Such fasteners may be thermally insulative andable to withstand high temperatures without deformation.

An electrical heating element 42 is positioned through heat reflector 44to distribute the heat in a desired manner. Other configurations arecontemplated. Heat reflector 44 can take on any number of shapes. Asexemplified in FIG. 2A, disposed within heat reflector 44 is athermoplastic ribbon 43 (e.g., TPE ribbon) having at least one embeddedheating element or wire and at least one embedded temperature sensor(e.g., a thermistor or thermocoupling). In an alternative embodiment(FIG. 2B), a heating element 41 (or cable) and temperature sensor 42 aredisposed within a channel of a thermal radiator 45 having a number offingers 46 protruding outwardly to heat cowl 16 and nearby structures.Other shapes for optimizing the spread of the heat efficiently andeffectively are contemplated. Heat reflector 44 may be made from variousmaterials. By way of non-limiting example, heat reflector 44 may be madefrom aluminum, thermally conductive plastics, stainless steel, andcombinations thereof. Heat reflector 44 may endure temperatures as highas 300° F. or 149° F. without any substantial melting or deformation. Aheat sink 47 (FIGS. 6 and 7) made of a highly conductive material suchas aluminum can be positioned between ribbon 43 and reflector 44 to aidin uniformly distributing heat along cowl 16.

The wiper blade and the cowl apparatus are in electrical communicationwith a controller 18 and a power source. The controller may optionallyinclude computer readable storage media for storing data representinginstructions executable by one or more processors or microprocessors.Computer readable storage media may include one or more of random accessmemory as well as various non-volatile memory such as read-only memoryor keep-alive memory. Computer readable storage media may communicatewith a microprocessor and input/output circuitry via a standardcontrol/address bus. As would be appreciated by one of ordinary skill inthe art, computer readable storage media may include various types ofphysical devices for temporary and/or persistent storage of data.Exemplary physical devices include but are not limited to DRAM, PROMS,EPROMS, EEPROMS, and flash memory. Controller 18 can be, and ispreferably, designed to use relays to control current to the heatingelements 22, 42, and preferably employs solid state components.

Controller 18 is configured to receive input from one or more sensorsregarding ambient temperature and may also receive input regardingwhether the engine is running, along with other input such as wiperblade temperature. By way of non-limiting example, controller 18 may beprogrammed such that, when it receives data indicating thresholdinitiation criteria are met, the controller causes power from powersource 46 to be directed to one or more of the heating elements 22, 42.Such initiation criteria may include temperature at or below a certaintemperature (such as, for example 5° C.) in combination with indicatorswhether the engine is running such as data indicating the crank shaftposition or voltage greater than 13 V. Exemplary alternative indicatorsof a running engine or operating vehicle may also include input from atachometer, vibration sensors accelerometer, a Hall effect sensors orcombinations thereof.

Controller 18 may be programmed such that, when it receives dataindicating threshold reduction criteria are met, the controller causespower from power source 46 to be reduced with respect to one or more ofthe heating element 22 of the wiper blade and the heating element 42 ofcowl 16. Such reduction reduces energy consumption and preventsoverheating and deterioration of heated components. Reduction criteriamay include voltage drop and movement. Exemplary reduction criteria mayalso include a reduction in vibration, an increase in ambienttemperature, an increase in wiper blade assembly and/or cowl,temperature, or combinations thereof. Temperature sensors may beemployed to detect ambient, wiper assembly and cowl temperatures. Forexample, an ambient air temperature sensor 60 can be located in theengine compartment away from heat generating or heat radiating sourcesto measure the outside air temperature. Ribbon 43 (shown incross-section in FIG. 8, as viewed along arrows VIII in FIG. 2A) canhave a plurality of heating elements and one or more wires 62 thatterminate at a temperature sensor (e.g., thermistor or thermocouple).Similarly, housing 28 can contain a temperature sensor 64.

Controller 18 may be programmed such that, when it receives dataindicating threshold stoppage criteria are met, the controller causespower from the power source to be stopped with respect to one or more ofheating element 22, 42. Such stoppage criteria may include voltage dropand movement. Exemplary stoppage criteria may also include a halt invibration, a high ambient temperature, a high wiper blade temperature,or combinations thereof.

Manual overrides to one or more of the initiation, reduction or stoppagethreshold may be included in the system. Option sensors that may provideinput to the controller include sensors that determine if the engine isrunning, ambient temperature and wiper blade temperature.

The combined system, with heated blades and a heated cowl aided by oneor more component comprising a thermally conductive plastic, provides asurprisingly advantageous result in that it is effective at melting andclearing ice and snow with a lower than expected pull on a power sourcesuch as a primary automotive battery or an auxiliary battery. In anembodiment where the housing of a wiper blade is made from thermallyconductive material, heating efficiency is expected to improve by over10%. In certain embodiments, the housing of the wiper blade heats toabout 45° C.

By using a combination of inputs to detect when an engine is running asopposed to using voltage increase alone, a surprising and unexpectedincrease in accuracy of when a heated wiper blade system shouldautomatically turn on and off is achieved. Many commercial vehicles haveaccessories such as snow plows, cabin heaters, and other components thatcan cause a voltage drop when activated. This voltage drop can cause thecontroller to shut off as it creates the same effect as when the engineis not running. By using a combination of inputs, the accuracy of thesystem is surprisingly increased. An example of this is to use voltagein conjunction with an accelerometer. When the voltage drops, the inputfrom the accelerometer will still detect the vehicle is moving and thecontroller will continue to operate.

Regarding the processes described herein, it should be understood that,although the steps of such processes have been described as occurring ina certain sequence, such processes could be practiced with the describedsteps performed in an order other than the exemplary order. It furthershould be understood that certain steps could be performedsimultaneously, that other steps could be added, or that certain stepsdescribed herein could be omitted. In other words, the descriptions ofprocesses herein are provided for the purpose of illustrating certainembodiments, and should in no way be construed so as to limit theclaimed invention.

Accordingly, it is to be understood that the above description isintended to be illustrative and not restrictive. Many embodiments andapplications other than the examples provided would be apparent uponreading the above description. The scope of the invention should bedetermined with reference to the appended claims along with the fullscope of equivalents to which such claims are entitled. It isanticipated and intended that future developments will occur, and thatthe disclosed systems and methods will be incorporated into such futureembodiments. In summary, it should be understood that the invention iscapable of modification and variation.

All terms used in the claims are intended to be given their broadestreasonable constructions and their ordinary meanings as understood bythose knowledgeable in the technologies described herein unless anexplicit indication to the contrary is made herein. In particular, useof the singular articles such as “a,” “the,” “said,” etc., should beread to recite one or more of the indicated elements unless a claimrecites an explicit limitation to the contrary.

What is claimed is:
 1. A wiper blade assembly comprising: a frame; awiper blade held by the frame; a heating element contacting at least oneof the wiper blade and frame; and a housing holding the frame, wiperblade and heating element, the housing composed of a polymeric materialhaving a thermal conductivity greater than 100 W/mK.
 2. The wiper bladeassembly of claim 1, wherein the polymeric material is selected frompolyamide-6, polyamide 6-6 and poly(acrylonitrile-butadiene-styrene). 3.The wiper blade assembly of claim 1, wherein the polymeric material is acomposite comprising a thermally conductive filler dispersed in acontinuous polymeric phase.
 4. The wiper blade assembly of claim 3,wherein the thermally conductive filler is selected from graphite,carbon black, carbon nanotubes, carbon fiber, copper, aluminum, boronnitride, aluminum nitride and beryllium oxide.
 5. The wiper bladeassembly of claim 4, wherein the continuous polymeric phase comprises atleast one of polypropylene, liquid crystal polymer, polyphthalamide,polyamide, polycarbonate, polyphenylene sulfide and thermoplasticelastomer.
 6. The wiper blade assembly of claim 4, wherein the thermallyconductive filler comprises from 20% to 60% of the volume of thecomposite.
 7. A wiper blade system, comprising the wiper blade assemblyof claim 1, and further comprising at least one of a wiper arm, anadapter, an adapter housing and a bracket composed of a polymericmaterial having a thermal conductivity greater than 100 W/mK.
 8. Thewiper blade system of claim 7, wherein the polymeric material isselected from polyamide-6, polyamide 6-6 andpoly(acrylonitrile-butadiene-styrene).
 9. The wiper blade system ofclaim 7, wherein the polymeric material is a composite comprising athermally conductive filler dispersed in a continuous polymeric phase.10. The wiper blade system of claim 9, wherein the thermally conductivefiller is selected from graphite, carbon black, carbon nanotubes, carbonfiber, copper, aluminum, boron nitride, aluminum nitride and berylliumoxide.
 11. The wiper blade system of claim 9, wherein the continuouspolymeric phase comprises at least one of polypropylene, liquid crystalpolymer, polyphthalamide, polyamide, polycarbonate, polyphenylenesulfide and thermoplastic elastomer.
 12. The wiper blade system of claim9, wherein the thermally conductive filler comprises from 20% to 60% ofthe volume of the composite.